The present invention relates to a device for controlling the rotary movement of a platen roller of a typewriter or any other office printing machine.
Normally, the rotary movement of the platen roller that is required for precisely positioning a sheet with respect to the line of typing of the printing arrangement, including in machines which are provided with electrical line spacing arrangements, is effected manually by operating side knobs which are coaxial with respect to the roller. The knobs are usually also provided with a clutch which releases the roller from the line spacing mechanism so that the manual rotary movements can be independent of the preset elementary line spacing value, for effecting micrometric positioning of the sheet of paper.